Soap product and process of making same



Oct. 26, 1943. F. E. JOYCE EIAL.

SOAP PRODUCT AND PROCESS -OF MAKING SAME Filed Jan. 27, 1943 Patented Oct. 26 1943 soar PRODUCT AND rnoonrss or MAKING SAME Floyd E. Joyce and Erik J. Lindhardt, Des Moines, Iowa, assignors to National By-Products, Inc., Des Moines, Iowa, a corporation of Iowa Application January 27, 1943, Serial No. 473,688

3 Claims.

Our invention relates to a process or method of manufacturing a finely divided soap product,

4 and to the product resulting from the process.

This application is a. continuation-in-part of our prior application, Serial No. 384,844, filed March 24, 1941.

A number of methods of producing a finely divided product are known in the soap industry. Some of these are described, for example, in United States Patents Nos. 1,621,506 and 1,652,- 900; they require an extensive array of complicated equipment to produce the finely divided -product, in addition to the equipment required for the ordinary initial process of manufacturing the soap. The complex character 01! the necessary equipment, and the space required for it, will be apparent upon reference to the patents mentioned. Some of the processes require careful and constant control of numerous rather critical physical variables, in order to give a satisfactory uniform commercial product.

There have been some processes known whereby finely divided products of relatively low soap content, those ordinarily known as "soap powders," could be manufactured, but none of these processes, so far as we are aware, utilize apparatus and procedures which work equally well for the production of a product of high soap content.

In such mechanical processes 01 making soap powders as are known to us, it has been necessary to add a liquid medium to the soap in order to take up the salts which are added to the mixture. This usually requires a crutching operation, involving extra time and expense, and special machinery.

According to other methods, finely divided soap products are made by mechanical fragmentation of hardened or solid soap. Processes of this type involve expensive steps for reducing the moisture content of the soap to the point where it can be shredded or ground without clogging up the machine used for the purpose.

It is an object of our invention to provide a process for producing finely divided soap which can be carried'out with a minimum of equipment in addition to that needed in a soap works for making soap by any of the commercial methods.

Another object is the provision of a type of process which can be carried out equally well, using the same apparatus, whether the product is a low soap content material (soap powder), a high soap content material (powdered soap). or even a substantially pure granulated soap.

Another object is the provision of a process wherein the step of granulating the soap can be carried out in the same apparatus used for mixing alkaline salts with the soap, where the product is one in which such mixture is required.

A further object is the provision of a method whereby very large amounts of suitable alkaline salts may be thoroughly mixed with hot kettle,

semi-boiled, cold process or rapid saponification soaps, without the addition of a liquid medium such as water or water-glass (aqueous solution of sodium silicate) to dilute the soap composition or break down solid gels. In previous methods, the necessity of adding such liquid mediums to get proper mixing has been attended with the consequent time and expense required after mixing for reducing the moisture content to the point where the soap would harden enough for handling or further processing.

Another object is the provision of a process in which tetrasodium pyrophosphate or other similar complex phosphates may be incorporated into a soap without the presence of water at high tem eratures, so that breakdown to orthophosphate is minimized.

Still another object is to provide a process in which all ingredients added to the soap can be mixed simultaneously instead of one at a time,

as is now common.

Another object is to provide a process in which essential oils or perfum s can be added during the granulating stage, so that thorough mixing is obtained without subjecting the oils or perfumes to high temperatures, which have an injurious effect on delicate odors.

Another'obiect is the production of a granulated filled soap which can be rolled to produce a thin chip or flake product having low density in bulk, and quickly and completely .soluble in water.

According to our invention, hot fiuid or semifiuid soap direct from the soap kettle, undiluted and uncrutched, is subjected to the action of a machine in which an intensive mixing is carried on as the soap cools. When the product is one in which alkaline salts or other filler materials are to be incorporated, they are subjected to the action of the machine simultaneously with the In the drawing we have illustrated certain apparatus with which our process may be carried out. It will be understood, of course, that performance oi. the process is possible with other apparatus, having an action similar to that of the particular kind shown. It is shown and described, however, in order that there may be a full and complete teaching of means by which our process may be successfully practiced.

In the drawing,

Figure 1 is a perspective view, looking from above, showing an intensive'mixer which may be used for carrying out our process.

Figure 2 is an elevational view, partly in vertical section taken on the line 2-2 of Figure 1;

Figure 3 is a diagrammatic representation of the rolls used when it is desired to convert the granular product resulting from the first stage of our process into a flake or chip product.

In Figures 1 and 2, the reference numeral l0 indicates generally a containing vessel in the nature of a circular stationary pan or tub. In the center is a post l2 within which a shaft I4 is rotated by suitable gearing l6 located below the pan. To the top end of the shaft a crosshead I8 is attached, so that it rotates with the shaft. Links 20 are pivoted to the crosshead so that they can swing about axes in a horizontal plane. On shafts 22 offset from the axes on which they are pivoted to the crosshead, the links 20 carry heavy revolving muller wheels 24. These wheels can roll on the bottom of the pan, or when there is material in the pan the link mounting allows the wheels to ride on the irregular surface of th material.

The shafts 22 are arranged so that the axes are offset, 1. e., do not pass through the axis of the vertical shaft H, as may be seen in Figure 2. Hence the muller wheels have a sideward sliding component as they rotate.

The links 20 have projections 26 extending above the crosshead, and carrying screws 28 which can be brought to bear against the crosshead, thus raising the muller wheels 24 off the bottom of the pan to any desired clearance distance. This adjustment makes it possible to eliminate excessive grinding of the materials.

Arms 21 on the links 20 carry scraper blades 29 which clean the surfaces of the wheels as they rotate.

Plows 30 and 32 are carried on the crosshead, the plow 30 being arranged toscrape material from the side and bottom of the pan I l and direct it into the path of the muller wheels, and the ploy 32 being arranged to scrape material from the sides the the post l2 and the bottom of the pan III, also direct it into the track of the wheels.

The result of the combined action of the plows and mullers is an intensive mixing, characterized by a very thorough, rapid and uniform distribution of the materials in the mixture.

To shorten the time required for processing a batch of soap by our method, the pan III is preferably provided with a water jacket 34 through which cold water may be circulated to cool the contents of the pan.

In the practice of our method, hot fluid soap is drawn from the soap kettle in fluid or semi-fluid condition, and without dilution or crutching is dropped directly into a mixing machine of the kind shown and described. If an unfilled product is desired, the soap is simply subjected to the intensive mixing action of the machine as it cools.

If a filled soap product is desired, the alkaline salts or other filler materials are placed in the mixing machine along with the fiuid soap. As the machine is operated, the combined action of the plows and mullers effects a very thorough, rapid and uniform distribution of the materials in the mixture. No crutching operation is required. There is no necessity for adding water of the mullers, and gradually the mass disintegrates into granules.

The muller wheels should be supported above the bottom by the screws 28, because it is only desired to reduce the soap mass to a granular or fragmentary character, but not to pulverize or powder it. The action differs from that of the ordinary edge-runner mill in that the function of the latter consists essentially in crushing, since the wheel runs or rests on the track or race. For the best exercise of applicants methc d, it has been found advisable to support the muller wheels 24 above the bottom of the pan by the adjusting screws 28 a distance which may be on the order of 3 to men. This avoids a grinding action which would produce a powdered product having some very fine components, diflicult to handle during the manufacturing process, Soap in too finely powdered form often tends to lump and agglomerate in water and thus remainfor a long time undissolved. Furthermore, the dusty fines float into the air when the soap is used, causing eye and nose irritation and sneezing.

Rotation of the crosshead at 25 R. P. M. gives good results, and, in general, speeds in the range of approximately 5-50 R. P. M. are satisfactory. Because of the slow speed of operation there is no problem of overheating, such as may be present in the use of high speed centrifugal mills. By our method, soaps having a temperature when drawn from the kettle of 150 to 260 F. can be readily handled. The temperature of the soap as it is run into the mixer is the highest temperature encountered. Throughout the process thereafter, the temperature is gradually lowered.

After the mixture has cooled somewhat, during the stage of granulation, essential oils or perfumes may be added. Our process has the advantage that these perfumes will be thoroughly and uniformly distributed throughout the mass, but need not be subjected to the high temperatures which must prevail in ordinary presentday mixing operationsor in subsequent drying operations.

Operation of the mixer is continued until the granules are brought to the desired uniformity of size and have cooled to an extent permitting satisfactory handling. The product is then discharged from the mixer and passed through a screen to remove any occasional lumps of soap. If a granular soap is desired, it is ready for packagingand use in this state, without any further processing.

The foregoing description applies to the first stage of our process. The hot fluid soap used may be full boiled, semi-boiled, cold process, or so-called rapid saponification sodium soap, in

' moisture contents ranging from 6% to 30%. The

process may be carried out without the addition of filler materials, or very large amo nts of dry inorganic alkaline salts or other materials may be incorporated into the hot soap, giving a uniform, homogeneous product. Hot finished soap can be granulated in less than thirty minutes, and the quantity which can be handled in each batch is limited only by the size of the mixer, which may be made in any practical size.

In its broader aspects our invention contemcooled steel rollers.

tween rolls.

assays? plates the preparation of soap powders such as those containing from about to about 25% of soap, or somewhat more or less; however, it is especially important and useful in connection with the preparation of powdered soaps or soap products containing at least 50% by weight of anhydrous soap, or of the order of 60% to 80% of anhydrous soap or more. Accordingly, we

make particular claims to the preparation of By ordinary methods of mixing, it is not possible to produce a filled soap which is suitable for rolling or ironing without an intermediate drying operation. Soap mixed by ordinary methods contains too much moisture, is not intensively mixed, and tends to form an incoherent, brittle product when ironed or rolled. Where drying is necessary, it requires time and involves the use of expensive equipment, occupying considerable space.

Granulated soap made by our process, however, is ready at once, and can be easily ironed or rolled into thin sheets by use of a system of water We have employed a series of three rolls arranged in a horizontal plane, each of the rolls being sixteen inches in diameter, forty inches long, and having a shell thickness of three and one-half inches. spective directions of rotation are diagrammatically represented in Figure 3. The roll sizes and speeds are not critical, but are indicated simply to show values which can be successfully employed.

The first roll, indicated in the drawing as 36, is operated at 6 R. P. M., the second one, 38, at 18 R. P. M., and the third, 40, at 54 R. P. Provision is made for adjustment of the spaces be- Soap granulated by our process is fed between rolls 36 and 38. In passing between these rolls, the particles are flattened and ironed out somewhat. They adhere to the roll 38, and are then carried between the rolls 38 and 40, being rolled still thinner. They adhere to the roll 40, and are scraped oil of it by a knife 42 extending along the roll. We thus obtain a thin, easily soluble flake product which in bulk weighs about one-third as much, fora given volume, as the granulated product.

The heets or flakes of soap produced by rolling may be broken up by screening to produce a fine, light weight, silky granulated soap.

As illustrations of various applications of our method, we give several examples.

A pure soap or high soap content product may be made as follows:

600 pounds of rapid saponification soap, at a temperature of 260 F., moisture content 6%, is dropped direct from the soap kettle, undiluted and uncrutched, into the mulling type intensive mixer. The mixer is set in motion, water is turned into the cooling compartment, and mulling is carried on while the mass of soap cools, solidifies and disintegrates into small granules under the action of the mixer. This may take about twenty minutes. Perfume is then added and the mulling is continued until the perfume is thoroughly mixed, requiring about five more minutes. The product is then dumped from the These rolls and their remixer and passed through a screen. The soap maybe packaged in the resulting form, as a relatively den e product, or it may be rolled as previously des ribed to give a quicker dissolving product of less density in bulk. After rolling, the soap is forced through a screen to make the particles more uniform in size. It is then ready for V packaging as a flake or chip product.

A typical filled soap product is made in the following manner:

500 pound of semi-boiled soap, temperature- 240 F., moisture content 10%, is fed direct from the soap kettle into the mulling type mixer in which water softening chemicals have been placed in the following amounts:

Pounds Soda ash 25 Tetrasodium pyrophosphate 60 Sodium metasilicate 5 Trisodium phosphate 15 or may at once be rolled and screened to make a chip or flake type of product.

The following procedure is representative of the making of a soap powder, or product high in inorganic salts and low in actual soap content, and illustrates the flexibility of our process:

200 pounds of finished full boiled kettle soap is dropped into the mulling type mixer. This soap may have a temperature of approximately F. and moisture content of 29%. Water may be worked into the soap by the mixer if desired before the chemicals are added, but it has certain disadvantages, as hereinafter pointed 0.417, and satisfactory mixing is achieved without the addition of water. The following chemicals are added:

Pounds Soda ash 300 Tetrasodium pyrophosphate 50 Sodium metasilicate 10 Trisodium phosphate-"- 25 Mulling is continued until all the ingredients bind together in a homogeneous mass, and then disintegrate into small particles. The resulting granulated product is ready for packaging and use.

A striking advantage of our method of making soap or soap products is in connection with the use of tetrasodium pyrophosphate or other similar complex phosphate as a filler material. Complex phosphates of this and related character are used in most of the commercial granulated SL aps. They aid the action of soap by sequestering the calcium and magnesium salts in hard water. In order to incorporate tetrasodium pyrophosphate into soap by ordinary methods, a liquid medium, such as water, must be employed. But when tetrasodium pyrophosphate is in intimate contact with the water at elevated temperature's i. e., under conditions existing in the ordinary crutching operation-it breaks down to orthophosphate to a considerable extent, thus losing much of its advantageous effect on hard water.

In our process, we can mix the pyrophosphate medium is required, and consequently there is substantially no breakdown oi the pyrophosphate. 1 The second example given above is representative. This method or introducing pyrophosphosphate was negligible.

In some cases, particularly where the soap as drawn from the kettle is in the higher temperature ranges, it may be preferable to add the pyrophosphate in the mulling device after the soaphas. cooled down somewhat, but while it is still plastic.

It will be seen from the foregoing description that by our invention we have provided a rapid and economical way of processing soap to give a finished product of either high or low density,

with the use of a minimum amount of equipment. We get a dry granular product in which we can incorporate filler materials without crutching, without the necessity of adding soda ashtocj take up water, and without any other drying operation. Our process can be employed for the making of a product with any proportion of soap from down to very low values. We can do everything necessary for the processing of the soap in one machine, without changing its mode of operation. The granular product obtained in the machine is suitable for rolling at once without drying or other intermediate processing.

When tetrasodium pyrophosphate is incorporated as a water softening agent, we get a product which difiers from any similar product known to us, in that the complex phosphate has not been subjected to breakdown by the presence of water at high temperature.

Some changes may be made in'the details of procedure involved in the practice of our method,

in the construction and arrangement oi the parts of the devices which we have described for carrying it out, and in the components of the product made by our process, without departing from the real spirit and purpose oi our invention. It is our intention to cover by our claims any variant modes oi! procedure, the use or any modified to semi-fluid hot soap, having a moisture content between about 6% and 30% and a temperature between not substantially below F. and up to about 260 F., introducing said soap into a vessel having mulling rotors carried. on a revolving crosshead therein, said rotors being supported sothat they run slightly above the bottom of said vessel, and slowly revolving said crosshead together with said rotors, while allowing the soap to cool, until the mass stiflens and is broken down into granules due to the action oLsaid mulling rotors.

2. The process 01' manufacturing a finely divided powdered soap comprising providing a hot, uncrutched fluid to semi-fluid soap having a moisture content between about 6% and about 30% and a temperature between not substantially below 150 F. and up to about 260 F., introducing said soap into a vessel, and rolling heavy rollers around on the material in the vessel while it cools, until the soap hardens and is broken up into particles.

3. A soap product made by introducing uncrutchedand undiluted fluid soap having a moisture content between 6% and 30% and a temperature between 150 F. and 260 F. into a vessel having mulling rotors carried on a revolving crosshead therein, and slowly revolving the crosshead together with said rotors while allowing the soap to cool, until the mass stifi'ens and is broken down into granules by the action 01' said rotors.

FLOYD E. JOYCE. ERIK J. LINDHARDT. 

